Structure And Property Of Modified Graphene Oxide Enhanced Aircraft Structural Corrosion Inhibiting Compounds Coatings

As an effective ways to control the production and expansion of metal corrosion,the aircraft structural corrosion inhibiting compounds(CICs)have been widely used in maintenance industry to improve safety margin.However,the protective film formed by CICs should be generally thinner to lighten the weight of the aircraft,resulting in the decrease of the anti-corrosion property.The anti-corrosion performance of CICs can be effectively improved by adding fillers.As one of the derivatives of graphene-based materials,Graphene oxide(GO)is rich in oxygen-containing functional,which is beneficial to increase the affinity to polar substances,but hinder its dispersion in the oily matrix.Functional modification of the material surface can effectively promote its distribution in weak-polar matrix.In view of the dispersion of GO in weak-polar matrix,based on the structure of the main components of CICs and the similar compatible principle,this thesis proposes to functionalize graphene oxide.Then,modified GO is firstly introduced into CICs to form composite coatings to investigate the influence of composite coatings composed of different modified products and CICs on the corrosion resistance of metal substrates,and to clarify the synergistic effect of the structure and concentration of modified GO on the anticorrosion and anti-aging property for different CICs.The specific research contents are as follows:GO with high oxidation degree is prepared using the improved Hummer method.The functionalization of GO is proposed based on the structure of the main components of CICs and the similar compatible principle.Next,the obtained GO and modified products is analyzed for the elemental,bonding methods,molecular structure and thermal stability,and the corrosion resistance of composite coatings composed by different modified products and CICs is studied to select the excellent modified products for further research.Combing the GO modified by dodecylamine(GO-DDA)and light aircraft structural corrosion inhibiting compounds(CIC-23)to prepare GO-DDA/CIC-23 composite coating.The SEM results of the coating section show that filler GO-DDA can improve the defect of uneven dispersion of filler GO.Through electrochemical testing of the composite coating,we finds that with the increase of filler content the corrosion resistance of the GO-DDA/CIC-23 composite coating shows a certain increase trend until its critical content(1.2%),after which GO-DDA nanosheets may form a micro-conducting path from the metal surface to the outermost edge of the coating,accelerating corrosion of metals.Furthermore,the anti-aging properdity of composite coating for a total of 30 day in UV-condensation environment is further analyzed.The Fourier Transform Infrared Spectroscopy(FT-IR)test results illustrate that aging is just a physical destruction and the chemical structure of all samples is hardly changed.In addition,we also find that the protection efficiency(PE)of GO-DDA/CIC-23 composite coating(71.88 %)is much higher than the CIC-23 coating(41.52 %)after artificial accelerated UV-condensation exposure experiments.The GO-DDA can effectively improve the anti-corrosion property and anti-aging property of CIC-23 matrix.GO-DDA is combined with heavy aircraft structural corrosion inhibiting compounds(CIC-35)to prepare GO-DDA/CIC-35 composite coating,with a view to full play the outstanding corrosion resistance property of CIC-35 and the advantages of lightweight and prominent barrier property of modified GO.The morphology analysis of the composite coating shows that GO-DDA can also be uniformly dispersed in the CIC-35 matrix.The electrochemical test demonstrate that with the increase of filler concentration within a certain range,the corrosion resistance of the composite coating will increase until the critical concentration(2.0%)is reached,after which GO-DDA nanosheets may form a micro-conducting path from the metal surface to the outermost edge of the coating,accelerating corrosion of metals.Artificial accelerated UV-condensation aging experiments on composite coating with optimal fillers ratio is carried out to study the influence on anti-aging property of fillers on substrate during 30 days experiment.The PE value of the GO-DDA/CIC-35 composite coating is still as high as 88.26 % after 30 days of aging,which is close to the PE value of un-aging CIC-35 coating(89.69 %),elaborating that the introduce of GO-DDA significantly enhance the anti-aging property of CIC-35 matrix.At the same time,we find that the composite coating composed of CIC-35 matrix has more superior corrosion resistance and anti-aging performance compared with CIC-23 matrix.Therefore,we believe that the introduction of modified GO can effectively improve the anti-corrosion property of CICs and reduce the weight of coatings in this research,which has enormous guiding value for the application of GO in the filed of anticorrosion of aircraft.